Microstructure of laterally oxidized Al{sub x}Ga{sub 1{minus}x}As layers in vertical-cavity lasers
- Sandia National Laboratories, Albuquerque, New Mexico 87185-1056 (United States)
We have studied the lateral oxidation of Al{sub x}Ga{sub 1{minus}x}As (x=0.98 and 0.92) layers contained in vertical-cavity lasers using cross-sectional transmission electron microscopy. We find a fine-grained ({approximately}4 nm) cubic spinel phase of Al{sub 2}O{sub 3} in both the 2{percent} Ga- and 8{percent} Ga-oxidized layers. The 8{percent} Ga-oxidized layers contract vertically by 6.7{percent} and not the expected 20{percent} for a fully dense Al{sub 2}O{sub 3} layer, with the 2{percent} Ga-oxidized layers showing a similar contraction. We observe a {approximately}17-nm-thick amorphous interface between the oxidized and unoxidized Al{sub x}Ga{sub 1{minus}x}As layers, which may account for the excellent electrical properties of these devices. We also observe metastable amorphous cavities associated with the moving reaction front. We infer the reaction proceeds from an initial amorphous phase that then transforms to a porous {gamma}-Al{sub 2}O{sub 3} layer.
- Research Organization:
- Sandia National Laboratory
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 285527
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 1 Vol. 69; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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